It was a slow day at work.
They were throwing out a water trap because the regulator was poked.
I saw an oportunity.
Removed the sacraficial anode and drilled out the regulator assembly and tapped thread. Made up a top blanking plate where the regulator adjuster fitted, made up a downpipe, cut some alu scrubbing wool and hey presto...a redneck engineered scrap parts oil catch can.
I'll add a proper drain tap and pipe later.

On your "oil seperator" , you have used a blue soft airline pipe for draining the unit . That blue pipe will not last very long with oil and high under bonnet temperatures . Rather use the black nylon pipe , as used on trucks . Don't fold it over , just heat the end with a heat gun or flame and then quickly and gently squeeze the end closed in a vice or with pliers . That's how you make plugs or stop ends for push lock airlines . What a great idea for something you were going to throw out as scrap !